KR102309726B1 - Communicating method in a wireless communication system using bean forminig and system thereof - Google Patents

Abstract

The present invention relates to a communication method and system in a wireless communication system using a beamforming method, and more particularly, to a method and system for obtaining beamforming information between transmitting and receiving devices in a beamforming system.
A transmission method according to an embodiment of the present invention is a method for performing communication in a transmission apparatus of a wireless communication system that performs wireless communication in a beamforming method, and assigns an identifier to all transmission beam directions that can be transmitted, and each transmitting a beam identifier and a reference signal allocated for each direction; checking whether or not there is an error by examining the error detection information when identifier information and error detection information for a receivable beam direction are received from a receiving device; and transmitting a response signal to the receiving device according to the presence or absence of the checked error, and performing data transmission/reception based on the received beam information when there is no error as a result of the error detection information check. have.

Description

COMMUNICATION METHOD IN A WIRELESS COMMUNICATION SYSTEM USING BEAN FORMINIG AND SYSTEM THEREOF

The present invention relates to a communication method and system in a wireless communication system using a beamforming method, and more particularly, to a method and system for acquiring beamforming information between transmitting and receiving devices in a beamforming system.

As we enter the information age, the amount of information processed in various fields is increasing, and the quality is greatly improved. Accordingly, information could be transmitted with only a small amount of data in the past, but more and more data processing is required. According to this quantitative and qualitative expansion, the demand for data traffic also increases in the wireless communication system. In order to satisfy this phenomenon, wireless communication systems are developing in the direction of supporting higher data rates.

A 4G (4th Generation) wireless communication system, which is currently being commercialized, has mainly pursued technology development in the direction of improving spectral efficiency in order to increase data rate. However, it is difficult to satisfy the rapidly increasing demand for wireless data traffic using only the frequency efficiency improvement technology.

As one method for solving this problem, there is a method of using a very wide frequency band. However, a frequency band currently used in a mobile communication cellular system is generally less than 10 GHz, so it is very difficult to secure a wide frequency band. Therefore, there is a need to secure a broadband frequency in a higher frequency band. However, only securing a broadband frequency in a higher frequency band cannot realistically solve all problems. This is because the path loss of radio waves increases as a higher frequency band is used for wireless communication.

When a high-band frequency is used, there is an advantage in that a wider frequency band can be secured, but the radio wave arrival distance is relatively short, and thus a service area is reduced. Therefore, it is necessary to solve the problem of the reduction of the service area due to the shortening of the radio wave reach.

There is a beam forming technology as one of the methods for alleviating the path loss of radio waves caused by the use of a high band frequency and reducing the service area. The beamforming technique can be divided into two types according to the subject. For example, the beamforming technique may be divided into a transmit beamforming technique performed by a transmitting device and a receive beamforming technique performed by a receiving device from the beamforming technique.

For such transmission beamforming or reception beamforming, a plurality of antennas have the form of an aggregated antenna array, and each antenna included in the antenna array becomes an array element. The shape of the antenna array may be implemented in various forms, such as a linear array and a planar array.

In general, the transmission beamforming method is a method of increasing directivity by using a plurality of antennas to concentrate an arrival area of radio waves in a specific direction. By using the transmission beamforming method, it is possible to increase the directivity of a signal to increase the arrival distance of radio waves. Furthermore, since the signal is hardly transmitted in a direction other than the direction in which it is directed, signal interference can be greatly reduced from the side of the receiving device.

The reception beamforming method is a method of performing beamforming on a reception signal using a reception antenna array. The reception beamforming may concentrate the reception of radio waves in a specific direction to increase the sensitivity of a reception signal coming in the corresponding direction. In addition, a signal coming from a direction other than the corresponding direction may be excluded from the received signal. Accordingly, the receiving device may increase a gain in a specific direction and block an interference signal in another direction.

When the above-described beamforming technique is used, traffic transmission/reception can be performed only when information on beamforming is shared between the transmitting apparatus and the receiving apparatus. For example, when the transmission beamforming direction in the transmission apparatus and the reception beamforming direction in the reception apparatus are different from each other, it may be determined that data transmission/reception is impossible or that the channel condition is very poor. Therefore, it is possible to efficiently transmit/receive traffic only by sharing information on beamforming between devices using transmit beamforming and/or receive beamforming.

Accordingly, the present invention provides a method and a system for sharing beamforming information between a transmitting apparatus and a receiving apparatus.

In addition, the present invention provides a method and system for minimizing a beamforming error between a transmitting apparatus and a receiving apparatus.

A transmission method according to an embodiment of the present invention is a method for performing communication in a transmission apparatus of a wireless communication system that performs wireless communication in a beamforming method, and assigns identifiers to all transmission beam directions that can be transmitted and each transmitting a beam identifier and a reference signal allocated for each direction; checking whether or not there is an error by checking the error detection information when identifier information and error detection information for a receivable beam direction are received from a receiving device; and transmitting a response signal to the receiving device according to the presence or absence of the checked error, and performing data transmission/reception based on the received beam information when there is no error as a result of the error detection information check; have.

A reception method according to an embodiment of the present invention is a method for performing communication in a reception apparatus of a wireless communication system that performs wireless communication in a beamforming method, and transmits a reference signal from all reception beam directions that can receive a signal. checking the quality of; selecting a beam direction having a communication quality among the received beam directions; transmitting a feedback signal including a transmission beam identifier of the selected beam direction and information for error checking to the transmission apparatus; and determining a beam direction for communication according to the response signal received from the transmitter.

By using the apparatus and method according to the present invention, information on beamforming can be shared between devices using transmission beamforming and/or reception beamforming, so that traffic can be efficiently transmitted/received, and the transmission device and It is possible to minimize beamforming errors between receiving devices.

1 is a conceptual diagram for explaining beamforming in a wireless communication system to which the present invention is applied;
2 is a signal flow diagram for sharing beamforming information between a transmitting apparatus and a receiving apparatus according to an embodiment of the present invention;
3 is a signal flow diagram when beamforming and transmitting a response signal between a transmitting apparatus and a receiving apparatus according to an embodiment of the present invention;
4 is a signal flow diagram when beamforming and transmitting a response signal between a transmitting apparatus and a receiving apparatus according to another embodiment of the present invention;
5 is a signal flow diagram in the case of transmitting a response signal between a transmitting apparatus and a receiving apparatus according to another embodiment of the present invention;
6 is a functional internal block diagram of a transmitting apparatus according to an embodiment of the present invention;
7 is a functional internal block diagram of a receiving apparatus according to an embodiment of the present invention;

Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. In this case, it should be noted that in the accompanying drawings, the same components are denoted by the same reference numerals as much as possible. In addition, it should be noted that the drawings of the present invention attached below are provided to help the understanding of the present invention, and the present invention is not limited to the form or arrangement illustrated in the drawings of the present invention. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. In the following description, only parts necessary for understanding the operation according to various embodiments of the present invention will be described, and it should be noted that descriptions of other parts will be omitted so as not to obscure the gist of the present invention.

1 is a conceptual diagram for explaining beamforming in a wireless communication system to which the present invention is applied.

Referring to FIG. 1 , data and/or signals may be transmitted/received through a predetermined wireless channel between a transmitting device 100 and a receiving device 110 . Transmission and reception are separated between the transmission device 100 and the reception device 110 for convenience of explanation, and both transmission and reception are possible. For example, when the transmitting device 100 transmits specific data or a signal to the receiving device 110, the transmitting device 100 operates as a transmitting device, but when receiving the data or signal transmitted by the receiving device 110, the transmitting device 100 operates as a receiving device It works. This may also be understood as the receiving device 110 . For example, the reception device 110 operates as a reception device when receiving data or a signal from the transmission device 100, but operates as a transmission device when transmitting data or a signal to the transmission device 100.

In addition, both the transmitter 100 and the receiver 110 according to the present invention are electronic devices capable of performing beamforming, and include a plurality of antennas. For example, the transmitting device 100 may include a first transmit antenna (TX_ANT_1), a second transmit antenna (TX_ANT_2), . , and an N-th transmission antenna (TX_ANT_N). The reception device 110 also includes a first reception antenna (RX_ANT_1), a second reception antenna (RX_ANT_2), . , and an N-th transmission antenna (RX_ANT_N). In general, when communicating through a radio channel between a transmitting device and a receiving device, the transmitting device and the receiving device may have the same number of antennas, and if they have different numbers of antennas, for example, the number of antennas of the transmitting device 100 is Nt. , when the number of antennas of the receiving device 110 is Nr, the maximum number of streams that can be simultaneously transmitted by the transmitting device 100 may transmit the maximum stream according to a value having the smaller number of antennas among the values of Nt and Nr. In the following description, for convenience of description, it is assumed that the transmitting device 100 and the receiving device 110 have the same number of antennas.

Also, referring to FIG. 1 , the transmitter 100 may transmit beams 11 , 12 , ..., 1M in various directions. In addition, the reception device 110 may also receive the beams 21 , 22 , ..., 2M received from various directions. 1 illustrates a case in which the number of beam directions that the transmitting device 100 can transmit and the number of beam directions that the receiving device 110 can receive are the same.

Also, in the example of FIG. 1 , only one transmitting device and one receiving device are illustrated in order to describe communication between one transmitting device and one receiving device. However, it is obvious that 1:N communication is possible using a multiple access method such as a base station and a portable terminal of a mobile communication system.

2 is a signal flow diagram for sharing beamforming information between a transmitting apparatus and a receiving apparatus according to an embodiment of the present invention.

The transmitting device 100 generates and transmits a reference signal in step 200 . In this case, the reference signal generated by the transmitting device 100 may be a mutually known signal between the transmitting device 100 and the receiving device 110 . Also, in step 200 , the transmitting device 100 according to the present invention may transmit the reference signal in all directions that the transmitting device 100 can transmit, for example, in M directions of FIG. 1 . In this case, the transmitting device 100 may transmit by adding identification information (or identifier) for identifying each direction in which beamforming can be performed when generating a reference signal, performing beamforming, and transmitting. Therefore, when the transmitter 100 can perform beamforming in M directions, identification information for identifying beamforming directions must be able to identify M cases. Also, the transmitting device 100 may beamform and transmit a reference signal and a signal including identification information for identifying a beam direction in each direction.

When the reference signal including the identification information is transmitted as described above, the receiving device 110 may measure the beams received from the transmitting device 100 in step 202 and select an optimal beam. As exemplified above, when the transmitting device 100 performs beamforming in M directions, the receiving device 110 may perform receive beamforming, and when a specific transmit beam performs beamforming in a specific receive beam direction, the signal quality is the best can do. In this case, the receiving device 110 may receive beamformed beams in multiple directions for beams transmitted in multiple directions by beamforming by the transmitting device 100 . Accordingly, the reception device 110 may determine the quality of each of the received transmission beams through reception beamforming. The receiving device 110 may use a signal-to-interference-noise ratio (SINR), a received power intensity (RSSI), or a combination of two or more methods to select an optimal beam when determining the quality.

As such, when the optimal beam is selected for the transmit beam and the receive beam, the receiving device 110 feeds back only the identifier information on the transmit beam or both the identifier information on the transmit beam and the information on the receive beam to the transmit device 100 in step 204 ( feedback) is possible. In this case, the reception device 110 may transmit by inserting a code capable of detecting an error in the transmission beam identifier information, for example, a CRC code, when feeding back the identification information on the transmission beam to the transmission device 100 . In this method, the CRC code can be used when transmitting the identifier information for the transmission beam by configuring it as one message. Alternatively, when the identifier information on the transmit beam is fed back, the identifier information on the transmit beam may be fed back based on a sequence rather than a message format. In this way, when the identifier information on the transmission beam is fed back based on a sequence rather than a message format, the error information may be detected using a threshold value-based method.

Therefore, the transmitting device 100 may receive a feedback signal including the transmit beam identifier information from the receiving device 110 in step 204, and proceed to step 206 to check the CRC code included in the transmit beam identifier information. If a CRC error occurs as a result of performing the CRC check, the transmitting device 100 may generate a negative acknowledgment signal (NACK signal) and transmit it to the receiving device 110 . On the other hand, if a CRC error does not occur as a result of performing the CRC check, the transmitter 100 may generate an acknowledgment signal (ACK signal) and transmit it to the receiver 110 .

The transmitting device 100 may transmit a negative response signal or an affirmative response signal according to a result of performing the CRC check, but the transmitting device 100 may perform an operation based on the negative response signal. For example, when no error occurs as a result of the transmission device 100 checking the CRC code included in the transmission beam identifier information received from the reception device 110, it may be configured not to transmit an acknowledgment signal (ACK signal). That is, the transmission device 100 is configured to transmit a negative acknowledgment signal (NACK signal) only when an error occurs as a result of checking the CRC code included in the transmission beam identifier information received from the reception device 110 . As such, in the present invention, both a negative response and an affirmative response may be used, and operation may be performed based on the negative response. As another example, similar to the method based on the negative response signal, it may operate based on the positive response signal.

In the example of FIG. 2 , a case in which both negative and positive responses are used is exemplified, and for convenience of explanation, descriptions will be made based on a case in which both negative and positive responses are used.

When an error occurs as a result of the CRC check in step 206, the transmitting device 100 proceeds to step 208 and transmits a negative acknowledgment signal (NACK signal) to the receiving device 110 . When receiving the negative acknowledgment signal as described above, the reception device 110 regenerates optimal beam selection information in step 210 and feeds back the transmission beam identifier information in step 212 . In this case, the receiving device 110 may be configured not to perform step 210 . For example, it is a case in which information on the beam generated in step 202 is stored in a predetermined time buffer or the like. In this case, the receiving device 110 may directly retransmit the signal stored in the buffer without performing step 210 . Also, the predetermined predetermined time may be, for example, a time slightly longer than the time until a negative response is received from the transmitting device 100 .

As such, when the receiving device 110 feeds back the transmit beam identifier information in step 212, the transmitting device 100 may receive it, and check the CRC code included in the transmit beam identifier information again in step 214. If there is no error as a result of checking the transmission beam identifier information in step 214 , the transmitting device 100 may generate an acknowledgment signal in step 216 and transmit it to the receiving device 110 .

The operation described above assumes that the transmitting device 100 transmits the reference signal in a preset period unit. Therefore, between the transmitting device 100 and the receiving device 110, it is necessary to measure the reference signal beam-formed in various directions in a preset period unit, and to perform a feedback operation therefor. That is, the operation of transmitting the reference signal by the transmitting device 100 in step 220 may have the same form as in step 200 described above, and may be performed in a preset time unit. After determining the transmission beamforming and reception beamforming methods using the reference signal as described above, the transmitting device 100 and the receiving device 110 may transmit and receive data traffic based on mutually determined beamforming information.

According to another embodiment of the present invention, it may be configured not to include steps 210 to 216. For example, when the transmission period of the reference signal transmitted by the transmitting device 100 to the receiving device 110 is very short, steps 210 to 216 may be not included. In this case, the same can be applied not only to the case of transmitting only the negative response of step 208 but also to the case of transmitting both the negative response signal and the positive response signal.

According to another embodiment of the present invention, the number of times the receiving device 110 performs steps 210 to 212 may be limited, such as two or three times. For example, even when the receiving device 110 transmits the retransmission twice or three times, if the CRC check result is an error in the transmitting device 100, unnecessary system resources may be wasted. For other reasons, the transmission device 100 may limit the number of retransmissions even when the transmission time of the next reference signal arrives soon.

According to another embodiment of the present invention, when the PDCCH is successfully received, the receiving device 110 receives the PDCCH through the transmission beams selected from the transmitting device 100 in the Nth transmission/reception beam selection process before a predetermined time and transmitted to the transmitting device 100. It is assumed that the apparatus (terminal) 110 successfully receives beam information transmitted to the transmitting apparatus (base station) 100 in the Nth transmission/reception beam selection process. However, this case may be applied to a case where the transmission beam that has been successfully updated between the transmitting device 100 and the receiving device 110 most recently among previous time points and the transmission beam information transmitted in the Nth transmission/reception beam selection process are different.

When the transmitting device 100 and the receiving device 110 share only the transmit beamforming identification information or the transmit beamforming identification information and the receive beamforming identifier together through the method described above, the receiving device 110 can receive data more efficiently. . As a result, this can increase the efficiency of the wireless communication system, and can improve the reliability.

As a system to which the method described above can be applied, various wireless communication systems that perform beamforming, such as a mobile communication system and a WiFi system, can be applied. Let us review the contents described above again under the following assumptions. It is assumed that the receiving device 110 is a terminal of a wireless communication system, and it is assumed that the transmitting device 100 is a base station of the wireless communication system.

Then, when the terminal 110 transmits an uplink control channel (e.g. PUCCH, etc.), a predetermined transmission beam is used between the base station and the terminal. For example, when transmitting an uplink control channel, the receiving device (terminal) 110 uses an optimal uplink transmission beam as long as the transmitting device (base station) 100 recently successfully instructed it, and the transmitting device (base station) 100 transmits the corresponding transmission. An uplink control channel is received using an optimal reception beam corresponding to the beam.

In other cases, when the transmitting device (base station) 100 does not explicitly indicate the transmission beam information each time when resource allocation, a predetermined transmission beam is used between the transmitting device (base station) 100 and the receiving device (terminal) 110. can In this way, in order for the operation scenario to operate normally without errors, the beam information between the base station and the terminal is maintained so that an error does not occur when transmitting the downlink optimal beam information measured by the terminal or the uplink optimal beam information measured by the base station to the base station or the terminal. should match

In addition, although the content described above as an example mainly exemplifies the operation scenario for the control channel, in the case of the data channel, more reliable communication is possible only when the beam information between the base station and the terminal matches.

In order to minimize the beam information mismatch between the base station and the terminal, when using the message as described above, when using the message, the CRC code is checked, and when using the sequence, the retransmission procedure can be performed based on the threshold value. Since the feedback procedure for the uplink transmission beam is the same as that for the downlink, the feedback procedure for the downlink transmission beam will be described as a reference. When the reciprocity between the uplink channel and the downlink channel is established, one of the feedback procedures for the downlink and uplink transmission beams may be omitted.

The receiving device (terminal) 110 may select a predetermined number of downlink beams through a reference signal transmitted by the transmitting device (base station) 100 and feed back information on the selected beams to the base station through uplink. Here, the predetermined number may be one or more values, and the determination of the number may be a value that the base station instructs in advance to the terminal or a value determined in a standard specification. In addition, a criterion for selecting a downlink beam may be a signal strength, a signal-to-interference noise ratio (SINR), or the like, and the selected downlink beam may be an optimal beam selected using the above-described criterion. Accordingly, the selected downlink beam may be an identifier or index information for identifying the downlink beam as described above.

In addition, as described above, since a CRC code is attached to the beam information fed back by the receiving device (terminal) 110, the transmitting device (base station) 100 transmits the beam information fed back by the terminal through a CRC check without error. Check that it has been received. In another embodiment, when the CRC is not added to the beam information fed back by the receiving device (terminal) 110, the transmitting device (base station) 100 determines the possibility of an error in the beam information fed back by the receiving device (terminal) 110 through an implementation algorithm. may be In general, the case of using CRC has higher error detection reliability.

The base station that has determined whether there is an error in the beam information fed back by the receiving device (terminal) 110 may transmit the error to the terminal through the following two methods. The first method may be a method based on an acknowledgment/negative acknowledgment (ACK/NACK) signal. When the beam information fed back by the receiving device (terminal) 110 is received without error, the transmitting device (base station) 100 may transmit an acknowledgment (ACK) signal to the receiving device (terminal) 110 . On the other hand, when a reception error occurs in the beam information fed back by the receiving device (terminal) 110, the transmitting device (base station) 100 may transmit a negative acknowledgment (NACK) signal. The second method is a method based on a negative acknowledgment (NACK) signal, and only when an error occurs in beam information fed back by the receiving device (terminal) 110, the transmitting device (base station) 100 requests the receiving device (terminal) 100 for retransmission . This second method is difficult to apply to the uplink transmission beam feedback procedure.

In the first method, the terminal receiving the NACK signal retransmits the beam information according to a predefined retransmission procedure. The predefined retransmission procedure can be variously defined, such as synchronous/asynchronous HARQ depending on whether the retransmission time is fixed, and adaptive/non-adaptive HARQ depending on whether the resource location and size are changed. can In the second method, the terminal receiving the retransmission request retransmits the beam information according to the base station request.

In the first method, when the terminal receives an acknowledgment (ACK) signal, beam information between the base station and the terminal is simultaneously updated based on the corresponding time point. Beam information between the base station and the terminal is simultaneously updated based on the viewpoint.

Thereafter, the base station continuously transmits a reference signal to the terminal, and the terminal measures beam-related information. In addition, the terminal transmits the corresponding beam information to the base station periodically or aperiodically in response to a request from the base station or in an event-triggered manner.

Next, when the transmitting device 100 transmits an acknowledgment signal (ACK signal) and/or a negative acknowledgment signal (NACK signal) to the receiving device 110, the beamforming method may be used. In this case, interference due to a response signal transmitted/received between the transmitting device 100 and the receiving device 110 may be very small from the viewpoint of the entire wireless communication system. However, when the response signal is transmitted using the beamforming method as described above, the probability that an ACK signal or a NACK signal may not be normally received increases. Because, when the alignment between the transmission beam and the reception beam for transmitting and receiving an ACK signal or a negative acknowledgment (NACK signal) is not correct, an ACK signal or a NACK signal is normally received because it may not be. Therefore, in the embodiment of the present invention described below, a method for reducing an error when transmitting an ACK/NACK signal using beamforming will be described.

3 is a signal flow diagram illustrating a case of beamforming and transmitting a response signal between a transmitting apparatus and a receiving apparatus according to an embodiment of the present invention.

Referring to FIG. 3 , the transmitting device 100 generates and transmits a reference signal in step 300 . In this case, the reference signal generated by the transmitting device 100 may be a mutually known signal between the transmitting device 100 and the receiving device 110 as described above. Also, in step 300 , the transmitting device 100 according to the present invention may transmit the reference signal in all directions that the transmitting device 100 can transmit, for example, in M directions of FIG. 1 . In this case, the transmitting device 100 may transmit including identification information for each transmission beam in each direction. For example, when the number of directions in which the transmitter 100 can perform beamforming is M, identification information for distinguishing the respective transmit beams may be added to each of the transmit beams from the first beam to the Mth beam.

As such, when the reference signal including identification information is transmitted for each transmission beam, the reception device 110 may measure each beam received from the transmission device 100 in step 302 and select an optimal beam. As exemplified above, when the transmitting device 100 performs beamforming in M directions, the receiving device 110 may perform receive beamforming, and when a specific transmit beam performs beamforming in a specific receive beam direction, the signal quality is the best can do. In this case, the receiving device 110 receives beams transmitted in multiple directions by beamforming by the transmitting device 100 by receiving beamforming in multiple directions. Accordingly, the reception device 110 may determine the quality of each of the received transmission beams through reception beamforming. The receiving device 110 may use a signal-to-interference-noise ratio (SINR), a received power intensity (RSSI), or a combination of two or more methods to select an optimal beam when determining the quality.

When the optimal beam is selected as described above, the reception device 110 may feed back identifier information on the optimal transmission beam to the transmission device 100 in step 304 . In this case, the reception device 110 may transmit by inserting a code capable of detecting an error in the transmission beam identifier information, for example, a CRC code, when feeding back the identification information on the transmission beam to the transmission device 100 . Even in this case, as described above, the sequence method may be used instead of transmitting the identifier information on the transmission beam using the message format. When the sequence method is used, as described above, an error may be detected using a threshold-based method or the like. In the following description, it is assumed that identifier information for a transmission beam is provided using a message format for convenience of description.

Accordingly, the transmitting device 100 may receive the feedback signal including the transmit beam identifier information received from the receiving device 110 in step 304, and proceed to step 306 to check the CRC code included in the transmit beam identifier information. If a CRC error occurs as a result of performing the CRC check, the transmitting device 100 may generate a negative acknowledgment signal (NACK signal) and transmit it to the receiving device 110 . On the other hand, if a CRC error does not occur as a result of performing the CRC check, the transmitter 100 may generate an acknowledgment signal (ACK signal) and transmit it to the receiver 110 .

As another example, when the receiving device 110 successfully receives the PDCCH through the transmission beams selected from the transmitting device 100 in the N-th transmission/reception beam selection process before a predetermined time and transmitted to the transmitting device 100, the receiving device (terminal) 110 is N It is assumed that beam information transmitted to the transmitting device (base station) 100 in the th transmission/reception beam selection process is successfully received by the transmitting device 100 . However, this case may be applied to a case where the transmission beam that has been successfully updated between the transmitting device 100 and the receiving device 110 most recently among previous time points and the transmission beam information transmitted in the Nth transmission/reception beam selection process are different.

At this time, in the present invention, when transmitting an acknowledgment or negative acknowledgment signal for the N-th transmitted reference signal, the response signal is transmitted using the recently successfully updated transmission beam between the transmitting device 100 and the receiving device 110 among the previous time points. can send

For example, when a positive response or negative response signal to the N-th transmitted reference signal is transmitted, the most recently successfully updated time between the transmitting device 100 and the receiving device 110 among the times before the N-th reference signal is transmitted is N If it is successfully updated based on the -1 th reference signal, a negative acknowledgment or acknowledgment signal may be transmitted in the N-1 th updated beam direction. As another example, when the most recently successfully updated time between the transmitting device 100 and the receiving device 110 among the time points before the time of transmitting the N-th reference signal is successfully updated based on the N-2th reference signal, the N-2th A negative or positive response signal can be transmitted in the updated direction. As described above, by using a beam that has been successfully updated between the transmitting device 100 and the receiving device 110 and already known to each other, it is possible to reduce the probability of transmission/reception error of the response signal.

In addition, when there are two or more successfully updated beams between the transmitting device 100 and the receiving device 110 most recently among previous time points, the transmitting device 100 informs the receiving device 110 in advance which beam to use to transmit a negative response or an affirmative response. can

Also, in the case of feeding back the transmission beam identifier information in step 304, the same method as described above may be used. That is, the transmission beam identifier information may be fed back in the most recently successfully updated beam direction among previous viewpoints.

This method may be continuously performed thereafter. For example, steps 310 to 318 correspond to steps 300 to 308 described above. Also, it should be noted that in FIG. 3 , an operation of transmitting or receiving data traffic in a mutually set beamforming direction after the transmission direction is set is omitted.

4 is a signal flow diagram illustrating a case of beamforming and transmitting a response signal between a transmitting apparatus and a receiving apparatus according to another embodiment of the present invention.

In the flowchart of FIG. 4 , the same operation or operations that can be inferred as described above, for example, a retransmission operation after transmitting a negative response, or an operation for data transmission and reception in a set beamforming direction, are omitted.

Referring to FIG. 4 , the transmitting device 100 generates and transmits a reference signal in step 400 . In this case, the reference signal generated by the transmitting device 100 may be a mutually known signal between the transmitting device 100 and the receiving device 110 as described above. Also, in step 300 , the transmitting device 100 according to the present invention may transmit the reference signal in all directions that the transmitting device 100 can transmit, for example, in M directions of FIG. 1 . In this case, the transmitting device 100 may transmit including identification information for each transmission beam in each direction. For example, when the number of directions in which the transmitter 100 can perform beamforming is M, identification information for distinguishing the respective transmit beams may be added to each of the transmit beams from the first beam to the Mth beam.

As such, when the reference signal including identification information is transmitted for each transmission beam, the reception device 110 may measure each beam received from the transmission device 100 in step 402 and select an optimal beam. As exemplified above, when the transmitting device 100 performs beamforming in M directions, the receiving device 110 may perform receive beamforming, and when a specific transmit beam performs beamforming in a specific receive beam direction, the signal quality is the best can do. In this case, the receiving device 110 receives beams transmitted in multiple directions by beamforming by the transmitting device 100 by receiving beamforming in multiple directions. Accordingly, the reception device 110 may determine the quality of each of the received transmission beams through reception beamforming. The receiving device 110 may use a signal-to-interference-noise ratio (SINR), a received power intensity (RSSI), or a combination of two or more methods to select an optimal beam when determining the quality.

When the optimal beam is selected as described above, the reception device 110 may feed back identifier information on the optimal transmission beam to the transmission device 100 in step 404 . In this case, the reception device 110 may transmit by inserting a code capable of detecting an error in the transmission beam identifier information, for example, a CRC code, when feeding back the identification information on the transmission beam to the transmission device 100 .

At this time, in the present invention, when the information on the beam selected with respect to the N-th reference signal is fed back, a response is made using the recently successfully updated transmission beam between the transmission device 100 and the reception device 110 among the time points before the reception of the N-th reference signal. signal can be transmitted.

Accordingly, the transmitting device 100 may receive a feedback signal including the received transmit beam identifier information from the receiving device 110 in step 404, and proceed to step 406 to check the CRC code included in the transmit beam identifier information. Thereafter, the transmitting device 100 checks whether an error exists as a result of checking the CRC code in step 408 . This may be a case in which there is no error in data received from the receiving device 110 . When there is no error as described above, the transmitting device 100 may transmit an acknowledgment (ACK) signal through the beam direction reported by measuring the N-th reference signal from the receiving device 110 . Since this is a case in which the received signal is normally received, it is affirmed by not performing beamforming in the direction most recently successfully updated among the time points before transmission of the N-th reference signal, that is, in a direction that may have been changed due to a change in the channel environment. The response signal can be transmitted more efficiently.

On the other hand, if there is an error as a result of checking the CRC code in step 408, it proceeds to step 412 and transmits a negative acknowledgment (NACK) signal by beamforming in the most recently successfully updated direction among the time points before transmission of the N-th reference signal. can do. Accordingly, step 410 or step 412 may be an operation performed selectively. For example, when step 410 is performed, step 412 is not performed, and when step 412 is performed, step 410 is not performed.

In addition, in order to support the receiving device (terminal) 110 having one receiving chain in the method shown in FIG. 4, the following method is possible. The transmitting device (base station) 100 transmits a negative acknowledgment (NACK) signal when an error occurs in the beam information fed back by the receiving device 110, and transmits a negative acknowledgment (ACK) signal to the terminal when no error occurs. In this case, the corresponding acknowledgment (ACK) signal is transmitted using the beam information received without error in the current Nth feedback step, and the negative acknowledgment (NACK) signal is transmitted most recently among the time points before the Nth reference signal transmission time. Transmission may be performed between the device 100 and the reception device 110 using the successfully updated transmission beam. Since there is only one reception chain, the reception device 110 receives an acknowledgment (ACK) or negative acknowledgment (NACK) signal by using an optimal reception beam corresponding to the transmission beam transmitted at the current nth feedback time.

As another embodiment for supporting the receiving device 110 having one receiving chain, there is the following method. The transmitting device 100 transmits a negative acknowledgment (NACK) signal when an error occurs in the beam information fed back by the receiving device 110, and transmits a negative acknowledgment (ACK) signal to the terminal when no error occurs. At this time, the acknowledgment (ACK) signal is transmitted using the beam information received without error in the current N-th feedback step, and the negative acknowledgment (NACK) signal is the most recently successfully updated beam information among the N-th previous time points. send using

Also, since the reception device 110 has one reception chain, the transmission device 100 transmits an acknowledgment signal in the p-th time interval and transmits a negative response signal in the q-th time interval. That is, in the case of an affirmative response, the signal is transmitted only in the p-th time interval, and the signal is not transmitted in the q-th time interval. Also, in the case of a negative response, the signal is transmitted only in the q-th time interval and no signal is transmitted in the p-th time interval. Since the signal transmission resource position indicates information of acknowledgment (ACK) and negative acknowledgment (NACK), the same signal can be transmitted regardless of a time interval (signal transmission resource position). Alternatively, in the case of an affirmative response, the signal may be transmitted in both the p and q-th time intervals, and in the case of a negative response, the NACK signal may be transmitted in both the p and q-th time intervals.

Although the above method is a method for supporting a terminal having one reception chain, it is not necessarily limited to a case where there is only one terminal reception chain.

Assuming that the above-described transmitting device 100 is a base station and the receiving device 110 is a terminal, additional contents will be described.

3 and 4, when an error occurs when the terminal receives the acknowledgment (ACK) signal transmitted by the base station and interprets it as a negative acknowledgment (NACK) signal, the terminal receives the acknowledgment (ACK) signal before a specific time or at a specific timing ), when the base station command to retransmit the beam information is not received, it is determined that there is an error in the negative acknowledgment (NACK) signal, and it can be corrected back to the positive acknowledgment (ACK) signal.

Conversely, when the base station transmits beam information to the terminal, an error occurs when the base station receives the acknowledgment (ACK) signal transmitted by the terminal and interprets it as a negative acknowledgment (NACK) signal, the base station sends the beam information back to the terminal retransmit

When the terminal interprets the negative acknowledgment signal transmitted by the base station as an acknowledgment signal because an error occurs when the terminal receives it, the base station requests the terminal to retransmit the beam information. Since the request for retransmission is transmitted based on the most recently successfully received transmit beam information by the base station, it is preferable that the terminal receives the request with a receive beam suitable for the corresponding transmit beam. Therefore, when the UE detects a positive signal, the UE may update the beam information after a specific time period instead of immediately updating the beam information. The specific time interval should be set to be larger than the time interval in which the base station can request retransmission from the terminal.

Conversely, if the base station interprets the negative response signal transmitted by the terminal as an affirmative response signal because an error occurs when receiving, the terminal determines that an error has occurred when the base station receives the negative response signal if the base station does not retransmit the beam information within a specific time and requesting beam information retransmission from the base station by using a beam information retransmission request message/channel.

5 is a signal flow diagram in the case of transmitting a response signal between a transmitting apparatus and a receiving apparatus according to another embodiment of the present invention.

Referring to FIG. 5 , the transmitting device 100 generates and transmits a reference signal in step 500 . In this case, the reference signal generated by the transmitting device 100 may be a mutually known signal between the transmitting device 100 and the receiving device 110 as described above. In addition, the transmitting device 100 according to the present invention may transmit the reference signal in all directions that the transmitting device 100 can transmit, for example, in M directions of FIG. 1 in step 500 . In this case, the transmitting device 100 may transmit including identification information for each transmission beam in each direction. For example, when the number of directions in which the transmitter 100 can perform beamforming is M, identification information for distinguishing the respective transmit beams may be added to each of the transmit beams from the first beam to the Mth beam.

As such, when the reference signal including identification information is transmitted for each transmission beam, the reception device 110 may measure each beam received from the transmission device 100 in step 502 and select an optimal beam. As exemplified above, when the transmitting device 100 performs beamforming in M directions, the receiving device 110 may perform receive beamforming, and when a specific transmit beam performs beamforming in a specific receive beam direction, the signal quality is the best can do. In this case, the receiving device 110 receives beams transmitted in multiple directions by beamforming by the transmitting device 100 by receiving beamforming in multiple directions. Accordingly, the reception device 110 may determine the quality of each of the received transmission beams through reception beamforming. The receiving device 110 may use a signal-to-interference-noise ratio (SINR), a received power intensity (RSSI), or a combination of two or more methods to select an optimal beam when determining the quality.

As such, the receiving apparatus receiving the reference signal including identification information for each transmission beam measures the quality of each transmission beam and determines L beams that can be used. Thereafter, the receiving device 110 generates information about the L beams that can be used in step 504, for example, identification information of each selected beam or/and information including quality information of the selected beam, and feeds it back to the transmitting device 100. have. In this case, the reception device 110 may transmit by inserting a code capable of detecting an error in the transmission beam identifier information, for example, a CRC code, when feeding back the identification information on the transmission beam to the transmission device 100 .

Accordingly, the transmitting device 100 may receive a feedback signal from the receiving device 110 in step 504 and may proceed to step 506 to check the CRC code included in the transmit beam identifier information. In this case, the feedback signal may include information including identification information of each selected beam or/and quality information of the selected beam as described above.

Thereafter, the transmitting device 100 determines the number of beams to be used when there is no error as a result of checking the CRC code in step 506 . In this case, the determined number of beams may determine beams to be used for communication based on L pieces of information reported by the reception device 110 that data communication is possible.

Here, in step 508, three cases may exist: step 508a, step 508b, and step 508c.

First, the transmitting device 100 may request retransmission when an error exists as a result of checking the CRC code in step 506 . In this case, the transmitting device 100 may request retransmission of beam information through a resource allocation control channel (PDCCH) in step 508a. That is, if there is no error as a result of checking the CRC code, retransmission is not requested, and only if there is an error, retransmission is requested through the PDCCH. In this case, when requesting retransmission on the PDCCH in step 508a, the transmitting device 100 may request retransmission by using the successfully updated transmission beam between the transmitting device 100 and the receiving device 110 at the most recent previous time point.

Accordingly, the receiving device 110 knows that the transmitting device 100 will transmit a PDCCH requesting retransmission by using the successfully updated transmit beam between the transmitting device 100 and the receiving device 110 at the most recent previous point in time. can be used to monitor and receive PDCCH.

Accordingly, if the PDCCH is not successfully received by the predetermined time or at the predetermined time, the reception device 110 may assume that the feedback signal of the transmission beams selected for the N-th received reference signal has been successfully received by the transmission device 100 . Alternatively, when monitoring and receiving the PDCCH, the receiving device 110 includes the most recently successfully updated transmission beam between the transmitting device 100 and the receiving device 110 among previous time points and the transmission beams transmitted in the Nth transmission/reception beam selection process. All suitable receive beams may be monitored and received.

Second, a case in which an error does not exist in the CRC test result as a result of the inspection in step 506 will be described. If there is no error in the CRC check result as a result of the check in step 506 , the transmitter 100 has successfully received information on L transmit beam identifiers from the receiver 110 as an optimal beam that can be used from the receiver 110 in step 504 . In this case, the transmitting device 100 may use all of the L transmission beams selected by the receiving device 110, or may use only some of the L transmission beams. Therefore, the transmitting device 100 may provide information on S beams having a number less than or equal to L to be used by the transmitting device 100 among the L transmit beam identifiers fed back by the receiving device 100 to the receiving device 110 through the PDCCH in step 508b. have. In this case, S may be an integer of “1” or more.

In addition, in this case, the transmitting device 100 may include a CRC for detecting an error in the transmitted information in data transmitted through the PDCCH. Accordingly, the reception device 110 may demodulate and decode the PDCCH in step 510 and determine whether the received data has an error through the received CRC check. In step 510, when the receiving device 110 determines the error, the PDCCH is received through the beam selected in the Nth transmission/reception beam selection process. Accordingly, if there is no error as a result of performing the CRC check on the received PDCCH, the reception device 110 may assume that the feedback of the transmission beams has been successfully received by selecting it from the N-th reference signal.

Third, let's take a look at another example in which there is no error in the CRC test result in the test result of step 506. If there is no error in the CRC check result as a result of the check in step 506, the receiving device 110 selects the optimal beams in the N-th transmission/reception beam selection process before a predetermined time from the transmitting device 100 and informs the transmitting device 100 of the optimal beams. is the case In this case, the transmitting device 100 may receive information on the received optimal beam in step 506 and, if there is no error as a result of the CRC check, transmit a PDCCH signaling general resource allocation in step 508c. That is, the PDCCH is successfully received through the transmission beams transmitted from the receiving device 110 to the transmitting device 100 . Therefore, when the receiving device (terminal) 110 receives the PDCCH signaling this general resource allocation, the receiving device (terminal) 110 transmits the beam information transmitted to the transmitting device (base station) 100 to the transmitting device (base station) 100 in the N-th transmission/reception beam selection process. Assume it has been successfully received. However, this case may be applied to a case where the transmission beam that has been successfully updated between the transmitting device 100 and the receiving device 110 most recently among previous time points and the transmission beam information transmitted in the Nth transmission/reception beam selection process are different.

Meanwhile, step 520 exemplifies a time point at which the reference signal is transmitted after step 500, and after step 512, packet data may be transmitted and received in a set beam direction.

6 is a functional internal block diagram of a transmitting apparatus according to an embodiment of the present invention.

Referring to FIG. 6 , the transmitting device 100 may include a transmitting device beamforming unit 601, a transmitting device error detecting unit 603, a transmitting device memory 605, and a transmitting device controlling unit 611. Each of the transmit antennas TX_ANT_1, TX_ANT_2, ... , TX_ANT_N may be connected to the transmitter beam shaping unit 601 .

The transmitter beam shaping unit 601 multiplies the reference signal to be transmitted by the factors for beam forming, so that each of the antennas TX_ANT_1, TX_ANT_2, ... , can be output as TX_ANT_N. Accordingly, each of the antennas TX_ANT_1, TX_ANT_2, ... , TX_ANT_N can shape the beam in various directions. The transmitter beam shaping unit 601 performs a band-up conversion of a radio processing unit, for example, a baseband signal to be transmitted into a band set for communication, and each antenna TX_ANT_1, TX_ANT_2, . . . , may include a configuration for down-converting a signal received by beamforming in TX_ANT_N. In addition, the transmitter beam shaper 601 may receive data transmitted through at least one or more specific transmission beams through at least one or more specific reception beam shaping under the control of the transmission device controller 611, which will be described later. Even at this time, the transmitter beam shaping unit 601 may perform reception beam shaping in a specific direction in order to receive a transmission beam in a specific direction under the control of the transmitter controller 611 .

The signal received by performing beam shaping in the transmitter beam shaping unit 601 is input to the transmitter error detection unit 603 . The transmitter error detection unit 603 may check whether there is an error in data received through a specific transmission/reception beamforming under the control of the transmitter controller 611 . For example, the data error check may be the CRC check described above. The transmitter error detection unit 603 may provide error check result information and/or information received through the transmission/reception beam to the transmitter controller 611 . For example, when there is no error in the received information as a result of the error check, the transmitter error detection unit 603 transmits information notifying that there is no error or information received through transmission/reception beam shaping with an indicator, for example, identifier information of a specific transmission beam. may be provided to the device controller 611 . If an error exists in the received information as a result of the error check, the transmitter error detection unit 603 may provide only information or an indicator indicating that the error exists to the transmitter controller 611 .

The transmitter controller 611 may control the transmitter beam shaper 601 to shape the transmit beam and shape the receive beam. Such beam shaping may be performed according to the method described with reference to FIGS. 1 to 5 described above. In addition, when the identifier information on the transmission beam is received from the receiving device 110 without error after transmitting the N-th reference signal, it is possible to control to store the received identifier information in the memory 605 of the transmitter.

The transmitter memory 605 has an area for storing data necessary for overall control of the transmitter 100, data generated during control, identifier information on a transmit beam, and transmit beam identifier history information controlled to be stored by the transmitter controller 611. can For example, the transmitter memory 605 may store information on a transmit beam successfully updated between the transmitter 100 and the receiver 110 at the most recent previous time point.

The transmitter controller 611 may set an optimal beam according to the method of FIGS. 2 to 5 described above by using the information stored in the transmitter memory 605 as described above.

7 is a functional internal block diagram of a receiving apparatus according to an embodiment of the present invention.

Referring to FIG. 7 , the receiving device 110 may include a receiving device beam shaping unit 701 , a receiving device beam quality measuring unit 703 , a receiving device memory 705 , and a receiving device controller 711 . Each of the receive antennas RX_ANT_1, RX_ANT_2, … , RX_ANT_N may be connected to the beam shaping unit 701 of the receiver.

The receiving device beam forming unit 701 receives each of the receiving antennas RX_ANT_1, RX_ANT_2, ... for beam forming a signal to be transmitted in a specific direction. , may be output by multiplying RX_ANT_N by factors. Accordingly, each of the receiving antennas RX_ANT_1, RX_ANT_2, ... , RX_ANT_N may shape the transmit beam and the receive beam in various directions. The receiving device beam shaping unit 701 performs a band-up conversion of a radio processing unit, for example, a baseband signal to be transmitted into a band set for communication, and receives antennas RX_ANT_1, RX_ANT_2, . . . , may include a configuration for down-band-converting a signal received by beamforming in RX_ANT_N. In addition, the receiver beam shaping unit 701 may receive data transmitted through at least one or more specific transmission beams through at least one or more specific reception beam shaping under the control of the reception device controller 711 to be described later. Even in this case, the receiver beam shaping unit 701 may perform reception beam shaping in a specific direction in order to receive a transmission beam in a specific direction under the control of the receiver controller 711 .

A signal received by performing beam shaping in the beam shaping unit 701 of the receiver is input to the beam quality measuring part 703 in the receiver. The receiver beam quality measuring unit 703 measures the quality of each of the transmission beams under the control of the receiver controller 711 . For example, when the transmitter 100 performs beamforming in two directions and the receiver 110 performs beamforming in two directions to receive, four cases occur. A pair of a transmission beam and a reception beam having a reception quality equal to or greater than a predetermined threshold value may be found among the received signals in response to each occurrence as described above. As such, information on a pair of a transmission beam and a reception beam having a reception quality equal to or greater than the threshold value is provided to the reception apparatus controller 711 .

The receiver control unit 711 may configure data in order to provide optimal transmit beam information to the transmitter 100 according to the method of FIGS. 2 to 5 described above. In this case, the receiver control unit 711 may include error detection information to enable error detection of the transmission beam information. The configured information may be provided to the transmitter 100 through the beamformer 701 of the receiver. Since the detailed description of such an operation has already been described above, a redundant description thereof will be omitted.

The receiver memory 705 stores data necessary for overall control of the receiver 110, data generated during control, identifier information on the transmit beam, identifier information on the receive beam, and various information controlled to be stored by the receiver control unit 711. You can have an area for In addition, the reception device memory 705 may store information on a transmission beam successfully updated between the transmission device 100 and the reception device 110 at the most recent previous time point.

On the other hand, the embodiments disclosed in the present specification and drawings described above are merely provided as specific examples to easily explain the contents of the present invention and help understanding, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be construed as including all changes or modifications derived based on the technical spirit of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

100: transmitting device 110: receiving device
11, 12, … , 1M: transmit beam direction
21, 22, … , 2M: receive beam direction
TX_ANT_1, TX_ANT_2, … , TX_ANT_N: transmit array antennas
RX_ANT_1, RX_ANT_2, … , RX_ANT_N: receive array antennas
601: transmitter beam shaping unit
603: transmitter error detection unit
605: transmitter memory
611: transmitter control unit
701: receiver beam shaping unit
703: receiver beam quality measurement unit
705: receiver memory
711: receiver control unit

Claims (17)

A method for performing communication in a transmitting apparatus of a wireless communication system that performs wireless communication in a beamforming method, the method comprising:
assigning identifiers to all transmitable transmit beam directions and transmitting a beam identifier and a reference signal assigned to each direction;
checking whether or not there is an error by examining the error detection information when identifier information and error detection information for a receivable beam direction are received from a receiving device;
transmitting a response signal to the receiving device according to the presence of the checked error, and performing data transmission/reception based on the received beam information when there is no error as a result of the error detection information check;
determining a beam direction to be used for transmission when receiving two or more pieces of identifier information on a receivable beam direction from the receiving device; and
Including; notifying the beam information to be used to the receiving device;
If there is an error as a result of the error detection information check, a resource allocation control channel using the beam successfully updated with the receiving device at the most recent previous time point for a retransmission request signal for the identifier information for the receivable beam direction Further comprising the step of transmitting through,
The identifier information includes an identifier assigned to the transmission beam direction and an identifier assigned to a receiveable beam direction,
A communication method in a wireless communication system using a beamforming method for transmitting the beam information to be used based on a beam determined from the transmitted reference signal when the information about the beam to be used is notified to the receiving device. According to claim 1, wherein the response signal,
A communication method in a wireless communication system using a beamforming method, which is one of an acknowledgment (ACK, Acknowledgment) signal, a non-acknowledgment (NACK, Non-Acknowledgment) signal, and the retransmission request signal. 3. The method of claim 2,
A communication method in a wireless communication system using a beamforming method for transmitting a reference signal in a beam direction obtained from the transmitted reference signal when transmitting the acknowledgment signal. According to claim 1,
A communication method in a wireless communication system using a beamforming method for transmitting a response signal to the receiving device in a transmission beam direction that has been successfully updated with the receiving device at the most recent previous time point. delete According to claim 1,
A communication method in a wireless communication system using a beamforming method for transmitting the beam information to be used based on a transmission beam successfully updated with the receiving device at the most recent previous time point when the beam information to be used is notified to the receiving device. delete According to claim 1,
In a wireless communication system using a beamforming method, one of a non-acknowledgment (NACK, Non-Acknowledgment) signal and the retransmission request signal is transmitted only when an error exists when transmitting a response signal to the receiving device according to the presence or absence of the error. communication method. 9. The method of claim 8,
A communication method in a wireless communication system using a beamforming method for transmitting the negative acknowledgment signal or the retransmission request signal in a transmission beam direction that has been successfully updated with the receiving apparatus at the most recent previous time point.
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